Power tool

ABSTRACT

A power tool ( 1 ) includes a brushless motor ( 8 ) having a stator ( 9 ) and a rotor ( 10 ). The stator ( 9 ) includes: a tubular stator core ( 60 ); front and rear insulators ( 61, 62 ) fixed to the stator core; and coils ( 64 ), which are wound around a plurality of teeth ( 63 ) on the stator core. The rotor ( 10 ) includes: a rotor core ( 67 ) disposed within the stator; a rotary shaft ( 11 ) fixed to the rotor core; and one or more permanent magnets ( 68 ) fixed to the rotor core. A sensor-circuit board ( 65 ) detects the position(s) of the permanent magnet(s) and is fixed to the stator. One or more notched parts ( 91 ) is/are formed, in an outer circumference of the sensor-circuit board, between circumferentially-adjacent teeth in an axial direction of the stator. The notch part(s) allow(s) air for cooling the brushless motor to pass more easily through the interior of the stator.

CROSS-REFERENCE

The present application claims priority to Japanese patent applicationserial numbers 2015-020491 and 2015-020492, both filed on Feb. 4, 2015,the contents of which are incorporated fully herein by reference.

TECHNICAL FIELD

The present invention relates to a power tool, such as a driver drill,that employs a motor having a wound-type stator.

BACKGROUND ART

Some known power tools, such as driver drills, utilize a motor (e.g., abrushless motor) having a wound-type stator that serves as its drivesource. If a brushless motor is employed, then, as disclosed in US2013/270932, electrically insulating members are respectively fixed toopposite ends of a stator core, which is formed by laminating aplurality of steel plates and which has a plurality of teeth (e.g., six)that protrude from an inner side of the stator core. Coils of each phase(all coils collectively constituting a multiphase winding wire) arerespectively wound around each pair of teeth, which are positioned withpoint symmetry, i.e. which are diagonally opposite of each other. Endparts of the coils are respectively connected to power-supply lines ofeach phase via terminals provided on the electrically insulatingmembers. A discoidal sensor-circuit board, which comprisesrotation-detection devices that detect the positions of permanentmagnets provided on a rotor, is attached to one of the electricallyinsulating members.

In addition, Japanese Laid-open Patent Publication 2009-303363 disclosesa stator of an electric motor that comprises six magnetic poles (teeth)that protrude from an inner side of the cylindrical stator core Again,coils of each phase are wound around point-symmetric pairs of the teeth,and all the coils collectively constitute a three-phase winding.

SUMMARY

A rotary shaft of the rotor is provided with a fan, and cooling of themotor is achieved by rotating the fan via the rotating rotary shaft,thereby causing cooling air to be drawn in from an outer part of thehousing and passed through the motor. However, in US 2013/270932,crossover wires of the coils, each crossover wire being of one phasecomponent and wound between the teeth of one pair, are wired along anouter circumference of the electrically insulating member attached tothe sensor-circuit board. Consequently a gap between the electricallyinsulating member and the sensor-circuit board is narrowed by thecrossover wires, thereby restricting the flow path for the cooling airto pass through. Therefore the coils cannot be effectively cooled.

In addition, in JP 2009-303363, if the three-phase winding is configuredon six teeth, then the coils of the phases are wired to the power-supplylines at, for example, 120° intervals. Consequently, the power-supplylines extend from the circumference of the stator in three radialdirections. To provide sufficient wiring space for the power-supplylines, the housing that houses the stator needs to be made larger in theradial direction, which adversely increases the size of the tool (i.e. acompact tool housing can not be achieved).

Accordingly, in one aspect of the present teachings, a power tool isdisclosed wherein coils of a stator can be more effectively cooled.

In addition or in the alternative, in another aspect of the presentteachings, wiring space for power-supply lines can be reduced, therebyenabling the size of the housing to be reduced.

In another aspect of the present teachings, a power tool comprises:

a motor, comprising:

a stator comprising: a tubular stator core; an electrically insulatingmember fixed to the stator core; and coils, which are wound around aplurality of teeth that protrude from an inner side of the stator core;

a rotor comprising: a rotor core disposed on an inner side of thestator; a rotary shaft fixed to the rotor core; and one or morepermanent magnets fixed to the rotor core; and

a sensor-circuit board for detecting the position(s) of the permanentmagnet(s) and being fixed to the stator;

wherein,

-   -   one or more notched parts (notch(es)) is (are) formed, in an        outer circumference of the sensor-circuit board, such that it is        (they are respectively) located between the teeth in an axial        direction of the stator.

In another aspect of the present teachings, the stator and thesensor-circuit board are fixed via fixing parts at at least twolocations arranged in a circumferential direction of the stator; and onenotched part is formed between the two fixing parts.

In another aspect of the present teachings, at least two notched partsare formed at at least two locations in a circumferential direction ofthe stator. In such an embodiment, the sensor-circuit board may comprisea connection part for holding one or more lead wires that output(s) oneor more detection signals, and the connection part may be disposedbetween the two notched parts.

In another aspect of the present teachings, the stator comprisesterminals respectively connected to the coils and the terminals arerespectively disposed in the notched parts.

In another aspect of the present teachings, there are six of the coilsand the notched parts are respectively formed at six locations. Each ofthe notched parts respectively exposes one of the coils in the axialdirection of the stator.

In another aspect of the present teachings, a power tool comprises:

a motor, comprising:

-   -   a stator, comprising: a tubular stator core; a first        electrically insulating member and a second electrically        insulating member fixed to front and rear end surfaces,        respectively, of the stator core; and coils, which are wound        around a plurality of teeth that protrude from an inner side of        the stator core; a rotor comprising: a rotor core disposed on an        inner side of the stator; a rotary shaft fixed to the rotor        core; and one or more permanent magnets fixed to the rotor core;        and    -   a sensor-circuit board for detecting the position(s) of the        permanent magnet(s) and being fixed to an outer-circumference        side of the first electrically insulating member;        wherein,

terminals, which are connected to the coils and connected topower-supply lines, are provided on the first electrically insulatingmember.

In another aspect of the present teachings, the sensor-circuit board isscrew fastened onto the first electrically insulating member.

In another aspect of the present teachings, there are three of theterminals and the coils are delta connected.

In another aspect of the present teachings, the terminals arerespectively disposed between adjacent pairs of the teeth.

In another aspect of the present teachings, there are at least two ofthe terminals. In such an embodiment, the sensor-circuit board maycomprise a connection part for holding one or more lead wires thatoutput(s) one or more detection signals, and the connection part may bedisposed between the two terminals.

In another aspect of the present teachings, a power tool comprises:

a motor, comprising:

-   -   a stator, comprising: a tubular stator core; electrically        insulating members respectively fixed to front and rear end        surfaces of the stator core; and coils, which are wound around a        plurality of teeth that protrude from an inner side of the        stator core;    -   a rotor, comprising: a rotor core disposed on an inner side of        the stator; a rotary shaft fixed to the rotor core; and one or        more permanent magnets fixed to the rotor core; and    -   a sensor-circuit board for detecting the position(s) of the        permanent magnet(s) and being fixed to the stator;        wherein,

a groove is provided, on an outer circumference of the stator core,along an axial direction of the stator; and

mating pieces, which mate with the groove, are respectively formedintegrally with the electrically insulating members.

In another aspect of the present teachings, a power tool, comprises:

a motor, comprising:

-   -   a stator, comprising: a tubular stator core; electrically        insulating members respectively fixed to front and rear ends in        an axial direction of the stator core;    -   and coils of three phases that are wound around six teeth that        protrude from an inner side of the stator core;    -   a rotor, comprising: a rotor core disposed on an inner side of        the stator; and a rotary shaft fixed to the rotor core; and    -   three terminals, which are held by one of the electrically        insulating members, the terminals being respectively connected        to one coil of each phase;        wherein,

all of the coils are formed by winding one winding wire sequentiallyaround the teeth, one phase component at a time; and

the three terminals are disposed inside an area of a semicircularportion of the stator core.

In another aspect of the present teachings, a crossover wire between theteeth, on which at least the coils of one phase are wound, is wired onthe other electrically insulating member side.

In another aspect of the present teachings, a power tool comprises:

a motor, comprising:

-   -   a stator, comprising: a tubular stator core; electrically        insulating members respectively fixed to front and rear ends in        the axial direction of the stator core; and coils of three        phases, which are wound around six teeth that protrude from an        inner side of the stator core;    -   a rotor, comprising: a rotor core disposed on an inner side of        the stator; and a rotary shaft fixed to the rotor core; and    -   three terminals, which are held by one of the electrically        insulating members,    -   the terminals being respectively connected to one coil of each        phase;        wherein,

all of the coils are formed by winding one winding wire sequentiallyaround the teeth, one phase component at a time; and

a crossover wire between the teeth, on which at least the coils of theone phase are wound, is wired on the other electrically insulatingmember side.

In another aspect of the present teachings, a rib that guides thecrossover wire is integrally formed with the other electricallyinsulating member.

In another aspect of the present teachings, a power tool comprises:

a motor, comprising:

-   -   a stator, comprising: a tubular stator core; electrically        insulating members respectively fixed to front and rear ends in        the axial direction of the stator core; and coils of three        phases, which are wound around six teeth that protrude from an        inner side of the stator core;    -   a rotor, comprising: a rotor core disposed on an inner side of        the stator; and a rotary shaft fixed to the rotor core; and    -   three terminals, which are held by one of the electrically        insulating members, the terminals being respectively connected        to one coil of each phase;        wherein,

at each of the terminals, the corresponding coils of one phase componentand the power-supply line to those coils are electrically connected(fused).

In at least some aspects of the present teachings, air for cooling themotor can pass more easily through the inner side (interior) of thestator owing to the notched part(s) provided in the outer circumferenceof the sensor-circuit board, which makes it possible to cool the coilsof the stator more effectively.

In addition or in the alternative, in at least some aspects of thepresent teachings, the space required for wiring the power-supply linescan be reduced, which makes it possible to make the housing morecompact, e.g., in the radial direction of the motor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a hammer driver-drill according to onerepresentative, non-limiting embodiment of the present teachings.

FIG. 2 is a rear view of the hammer driver-drill.

FIG. 3 is a longitudinal-cross-sectional view of the hammerdriver-drill.

FIG. 4 is an enlarged view of a main body portion.

FIG. 5 is an oblique view of a stator.

FIG. 6 is an exploded oblique view of the stator, wherein asensor-circuit board has been removed.

FIG. 7 is a plan view of the stator.

FIG. 8 is a plan view of the stator, wherein the sensor-circuit boardhas been removed.

FIG. 9 is a view in the direction of the arrow A that is shown on theleft side in FIG. 7. FIG. 10 is a view in the direction of the arrow Bthat is shown at the bottom in FIG. 7.

FIG. 11 is a cross-sectional view taken along (vertical) line A-A shownin FIG. 7.

FIG. 12 is a cross-sectional view taken along (horizontal) line B-Bshown in FIG. 7.

FIG. 13 is an enlarged view of section (encircled portion) C shown inFIG. 12.

FIG. 14 is a bottom view of the stator.

FIGS. 15A and B include schematic drawings showing a wire-windingmethod, wherein FIG. 15A shows a wiring-connection side and FIG. 15Bshows an opposite wiring-connection side.

FIGS. 16A and B include schematic drawings that show a modified exampleof the wire-winding method, wherein FIG. 16A shows a wiring-connectionside and FIG. 16B shows an opposite wiring-connection side.

FIGS. 17A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 17A shows awiring-connection side and FIG. 17B shows an opposite wiring-connectionside.

FIGS. 18A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 18A shows awiring-connection side and FIG. 18B shows an opposite wiring-connectionside.

FIGS. 19A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 19A shows awiring-connection side and FIG. 19B shows an opposite wiring-connectionside.

FIGS. 20A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 20A shows awiring-connection side and FIG. 20B shows an opposite wiring-connectionside.

FIGS. 21A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 21A shows awiring-connection side and FIG. 21B shows an opposite wiring-connectionside.

FIGS. 22A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 22A shows awiring-connection side and FIG. 22B shows an opposite wiring-connectionside.

FIGS. 23A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 23A shows awiring-connection side and FIG. 23B shows an opposite wiring-connectionside.

FIGS. 24A and B include schematic drawings that show another modifiedexample of the wire-winding method, wherein FIG. 24A shows awiring-connection side and FIG. 24B shows an opposite wiring-connectionside.

DETAILED DESCRIPTION

Embodiments of the present teachings are explained below, with referenceto the drawings.

The hammer driver-drill 1 shown in FIGS. 1-4 includes a handle 3 thatprotrudes downward from a main body 2 that extends in a front-reardirection. A drill chuck 4 is configured or adapted to grasp at its tipa bit and is provided on a front end of the main body 2. A battery pack5 serves as a power supply and is detachably mounted on a lower end ofthe handle 3. A housing 6 is formed by joining (assembling), usingscrews 7 extending in the left-right direction, left and right halfhousings 6 a, 6 b, which continuously form the handle 3 and a rear-halfportion of the main body 2.

A rear portion within the main body 2 houses a tubular stator 9 and arotor 10, which is disposed in an inner part (interior) of the stator 9.An inner-rotor type brushless motor 8 comprising a rotary shaft 11 ishoused in the rotor 10. A gear assembly 12 comprises a spindle 13 thatprotrudes forward from the housing 6. The gear assembly 12 is located(assembled) forward of the brushless motor 8 and serves to convert therotation of the rotary shaft 11 into a lower speed that is transmittedto the spindle 13. The drill chuck 4 is attached to a front end of thespindle 13. Below the main body 2, a switch 14 is housed in an upperpart of the handle 3, and a trigger 15 protrudes forward thereof. Amotor forward/reverse-changing button (reversing switch lever) 16 isprovided upward of the switch 14; forward thereof, an LED 17 thatilluminates forward of the drill chuck 4 is housed in a diagonallyupward orientation.

A mounting part 18, onto which the battery pack 5 is slidably mountedfrom the front, is formed on a lower end of the handle 3. The mountingpart 18 houses: a terminal block 19, which comprises terminals 19 a towhich the battery pack 5 is electrically connected; and a controller 20,which comprises a microcontroller (e.g., microprocessor, memory, etc.)that controls the brushless motor 8, six switching devices, etc., andwhereto the switch 14, the stator 9 of the brushless motor 8, and thelike are electrically connected. A strap-anchoring part 21 is providedon a rear surface of the mounting part 18 using a screw boss. Referencenumbers 22 are hook-attachment parts for detachably attaching a hookthat can be used to hang the power tool on a tool belt when thedriver-drill 1 is not in use. The battery pack 5 further includes arechargeable battery 23 (herein, a 10.8 V rechargeable battery providedwith three (lithium ion) battery cells), terminals 24, and a locking(latching) hook 25. The hook 25 can be released from a correspondinglatching part provided on the mounting part 18 by pushing down a button26 located on a front surface of the battery pack 5.

The gear assembly 12 includes a tubular first gear case 27, which islocated forward of the brushless motor 8, and a second gear case 28,which is affixed forward of the first gear case 27 and has a two-steptubular shape, i.e. it includes a large-diameter part 29 and asmall-diameter part 30. The first gear case 27 supports the rotary shaft11 via a bearing 31, and a tip of the rotary shaft 11, to which a pinion32 is attached, protrudes into the gear assembly 12.

A planetary-gear speed-reducing mechanism 33 includes three stages ofcarriers 35A-35C, which respectively support a plurality of planet gears36A-36C respectively revolving inside internal gears 34A-34C, disposedin an axial direction. The speed-reducing mechanism 33 is housed in aninner part of the gear assembly 12, and the pinion 32 of the rotaryshaft 11 meshes with the first-stage planet gear 36A. The second-stageinternal gear 34B is rotatable and moveable frontward and rearward inthe axial direction; at an advanced (forward) position, the second-stageinternal gear 34B is capable of meshing with a coupling ring 37, whichis held inside the large-diameter part 29.

A speed change lever 39, which is provided in the housing 6 such that itis capable of sliding frontward and rearward, is coupled to the internalgear 34B via a linking member 38. When the speed change lever 39 is slidrearward, the internal gear 34B retracts via the linking member 38 andmeshes with an outer circumference of the first-stage carrier 35A whilemaintaining the meshing with the second-stage planet gear 36B. In thisrearward position of the speed change lever 39, a high-speed moderesults in which the second-stage deceleration is omitted (cancelled).Conversely, when the speed change lever 39 is slid forward, the internalgear 34B advances, separating from the carrier 35A, via the linkingmember 38, and meshes with the coupling ring 37 while maintaining themeshing with the second-stage planet gear 35B, and thereby rotation isinhibited. In this forward (advanced) position of the speed change lever39, a low-speed mode results in which the second-stage decelerationfunctions.

A hammer mechanism that imparts percussion (hammering) to the spindle 13in the axial direction is provided on an inner side of thesmall-diameter part 30 of the second gear case 28. Furthermore, a clutchmechanism, which cuts off the transmission of torque to the spindle 13at a prescribed load on the spindle 13, is provided on an outer side ofthe small-diameter part 30. This design provides three switchableoperating modes, namely (i) a hammer-drill mode, in which the spindle 13is hammered while it rotates, (ii) a drilling mode, in which the spindle13 only rotates without being hammered, and (iii) a clutch mode (drivingmode), in which the transmission of torque to the spindle 13 is cut offat a prescribed load. Each of the operating modes and mechanisms will befurther explained in the following.

In the hammer (percussion) mechanism, the spindle 13 is axiallysupported by front and rear bearings 40, 41 inside the small-diameterpart 30, and a rear end of the spindle 13 is slidably coupled to thethird-stage carrier 35C. Between the bearings 40, 41 in the spindle 13,a ring-shaped first cam 42 and a ring-shaped second cam 43 areexternally mounted coaxially from the front. The first cam 42 has a camgear on its rear surface and is coupled to the spindle 13 via a spline.A cam gear is formed on the front surface of the second cam 43, and thesecond cam 43 is loosely placed around the spindle 13 and non-rotatablydisposed inside the small-diameter part 30.

Furthermore, forward of the first cam 42, a plurality of steel balls 45is held by a ring-shaped receiving plate 44 between the first cam 42 andthe bearing 40, and a cam plate 46 is provided between the steel balls45 and the first cam 42. An arm 47 extends rearward from the cam plate46. The arm 47 is linked via a linking plate 49 to a mode-changing ring48, which is rotatably joined (assembled) to the large-diameter part 29and is forward of the housing 6. When the linking plate 49 is rotated asa result of a manual rotation of the mode-changing ring 48, the firstcam 42 is slid rearward via the cam plate 46 and is caused to mesh withthe second cam 43.

In the clutch mechanism, a clutch ring 50 is externally mountedrotatably to the small-diameter part 30 forward of the mode-changingring 48. On an inner side of the clutch ring 50, a screw-feeding plate51, which screws onto a screw part formed on an outer circumference ofthe small-diameter part 30, is provided integrally rotatable with theclutch ring 50 and moveable in the axial direction. Rearward of thescrew-feeding plate 51, a front receiving plate 52 capable offorward-rearward movement in the axial direction is provided on thesmall-diameter part 30 in a state wherein the rotation of the frontreceiving plate 52 is restricted. A pressing plate 54, which makescontact with a front surface of a closure part 53 between thelarge-diameter part 29 and the small-diameter part 30, and a rearreceiving plate 55, which is forward thereof, are provided rearward ofthe front receiving plate 52. A plurality of coil springs 56 aredisposed, equispaced in a circumferential direction, between the frontreceiving plate 52 and the rear receiving plate 55.

In addition, rearward of the pressing plate 54, a plurality of steelballs 57 is held, such that the steel balls 57 are equispaced in thecircumferential direction, by the closure part 53. The steel balls 57contact a front surface of the third-stage internal gear 34C, which isrotatable, and are capable of engaging in a circumferential directionwith a clutch cam, which is not shown and is provided such that itprotrudes from the front surface of the internal gear 34C. A biasingforce of the coil springs 56, 56 is transmitted to the internal gear 34Cvia the steel balls 57, the pressing plate 54, and the rear receivingplate 55, and this biasing force causes the rotation of the internalgear 34C to be restricted or prevented. The clutch ring 50 isrotationally operated to screw-feed the screw-feeding plate 51 and thefront receiving plate 52 in the axial direction so as to change theaxial length of the coil springs 56, thereby making it possible tomodify the pressing (biasing) force imparted (applied) to the internalgear 34C.

Each operation mode will now be explained in the following. First, at afirst rotational position of the mode-changing ring 48, which is a phase(operation mode, i.e. the clutch mode) in which the cam plate 46 doesnot slide the first cam 42 rearward, the first cam 42 is disposedforward of the second cam 43 and does not mesh with the second cam 43.Consequently, the rotational operation of the clutch ring 50 results ina clutch mode in which the pressing (biasing) force imparted (applied)to the internal gear 34C is modifiable.

In this clutch mode, when the trigger 15 is squeezed to drive thebrushless motor 8, the rotary shaft 11 rotates and the spindle 13rotates via the planetary-gear speed-reducing mechanism 33, therebymaking it possible to perform a screw tightening operation or the likewith a driver bit mounted in the drill chuck 4. As the screw tighteningprogresses, the load imparted (applied) to the spindle 13 eventuallyexceeds the pressing (biasing) force of the coil springs 56 that fixes(holds) the internal gear 34C. When this happens, the clutch cam of theinternal gear 34C pushes out the steel balls 57, the pressing plate 54,and the rear receiving plate 55 forward, the internal gear 34C is idled,and thus the screw tightening ends (clutch operation).

Next, at a second rotational position at which the mode-changing ring 48has been rotated by a prescribed angle from the clutch mode, arestraining ring 58, which is provided on the mode-changing ring 48,engages with the rear receiving plate 55, thereby restricting theadvance of the rear receiving plate 55. Consequently, the drilling moderesults wherein the movement of the pressing plate 54 forward iscontinuously restricted (prevented) regardless of the pressing (biasing)force of the coil springs 56.

When the spindle 13 is rotated in the drilling mode, regardless of theload imparted (applied) to the spindle 13, the steel balls 57 do notride over the clutch cam of the internal gear 34C, and consequently therotation of the spindle 13 continues while the fixed state of theinternal gear 34C remains unchanged. Furthermore, at this time too, thefirst cam 42 does not slide rearward, and consequently hammering(percussion) on the spindle 13 does not occur.

Furthermore, at a third rotational position at which the mode-changingring 48 has been further rotated by a prescribed angle from that of thedrilling mode, the cam plate 46 slides the first cam 42 rearward.However, the engagement of the restraining ring 58 and the rearreceiving plate 55 does not change. Consequently, a hammer mode resultswherein the first cam 42 and the second cam 43 engage. When the spindle13 is rotated in the hammer mode, the first cam 42, which rotatesintegrally with the spindle 13, engages with (slides over) the secondcam 43 fixed inside the small-diameter part 30, and consequentlyhammering (percussion) on the spindle 13 occurs. Furthermore, becausethe fixed state of the pressing plate 54 does not change owing to therestraining ring 58, the rotation of the spindle 13 continues regardlessof the load imparted (applied) to the spindle 13.

Turning now to the details of the motor 8, the stator 9 of thethree-phase brushless motor 8 is held, with the front-rear directionserving as the axis, by ribs 59, 59 formed on inner surfaces of the halfhousings 6 a, 6 b. As shown in FIG. 5 to FIG. 8, in the stator 9, aring-shaped (annular) front insulator 61 and a ring-shaped (annular)rear insulator 62, which are electrically insulating members, areassembled (joined) onto front and rear end surfaces, respectively, of astator core 60, which is formed by laminating (stacking) a plurality ofsteel plates. In addition, coils 64 are respectively wound around sixteeth 63 that protrude from an inner side of the stator core 60.Further, rotation-detection devices 66 (e.g., Hall effect sensors) areinstalled on a sensor-circuit board 65 and detect the positions ofpermanent magnets 68 provided on the rotor 10. The sensor-circuit board65 is screw fastened onto a front surface of the front insulator 61.

Optionally, the sensor-circuit board 65 may include atemperature-detecting device that generates a temperature-detectionsignal, which is input to the controller 20. In such an embodiment, thecontroller 20 monitors the temperature-detection signal and stops thecontrol (operation) of the brushless motor 8 at a prescribed (upperlimit) temperature. In such an embodiment, damage caused by an excessivetemperature of the brushless motor 8 of the 10.8 V hammer driver-drill 1can be reliably prevented.

Referring again to FIGS. 3 and 4, the rotor 10 comprises: asubstantially cylindrical rotor core 67, which is formed by laminating(stacking) a plurality of steel plates and is disposed around the rotaryshaft 11. Four plate-shaped permanent magnets 68 (e.g., sinteredmagnets) are fixed to an inner part of the rotor core 67. The permanentmagnets 68 are inserted into through holes, which are formed such thatthey are located, in a transverse cross-section of the rotor core 67, onfour sides of a square centered on the rotary shaft 11, and are fixed byan adhesive and/or by press fitting.

A rear end of the rotary shaft 11 is axially supported by a bearing 69,which is held by a rear part of the housing 6. A centrifugal fan 70 isattached to the rotary shaft 11 at a position forward of the bearing 69.Air-exhaust ports 71 are formed in left and right side surfaces of thehousing 6 proximal to the location of the centrifugal fan 70, andair-suction ports 72 are provided in side surfaces of the housing 6 thatcontact outer sides of the stator 9 (see FIG. 1).

A rear stopper 73 is provided between the rotor core 67 and thecentrifugal fan 70. The rear stopper 73 is a brass disc and has an outerdiameter the same as that of the rotor core 67; it is fastened to therotary shaft 11 coaxially with the rotor core 67. A front stopper 74 isprovided on an inner side of the sensor-circuit board 65 between therotor core 67 and the bearing 31 on the front side. The front stopper 74is also a brass disc, but has an outer diameter smaller than that of therotor core 67; it is fastened to the rotary shaft 11 coaxially with therotor core 67 and such that the front stopper 74 is spaced apart fromthe rotor core 67 with a gap in between. However, the outer diameter ofthe front stopper 74 is larger than that of an inner-side circlevirtually defined by the positions of the four permanent magnets 68.Furthermore, the front stopper 74 is located forward of the permanentmagnets 68.

The structure of the stator 9 will now be discussed in further detail.More particularly, the stator 9 is shown in FIG. 5 to FIG. 14 removedfrom the power tool and will be explained with the understanding thatthe front insulator 61 side is set upward and the rear insulator 62 sideis set downward.

Six grooves 75 are formed in the axial direction, equispaced in thecircumferential direction, on an outer circumference of the stator core60. Mating pieces 76 are formed integrally with or on each of the frontinsulator 61 and the rear insulator 62 in the axial direction. Themating pieces 76 respectively mate with (are press-fitted into) endportions of the grooves 75. The press fitting of the mating pieces 76into the grooves 75 makes it possible to resist warpage of the front andrear insulators 61, 62 and to rigidly integrate (connect) the statorcore 60 with the front and rear insulators 61, 62. On both sides of oneof the grooves 75 of the stator core 60, projections 77 are formed alongthe groove 75. The engagement of the projections 77 in a not-shownengaging groove, which is provided on an inner surface of the housing 6,makes it possible to rotationally lock the stator 9 and to position thestator 9 forward and rearward. In addition, along an extension of theprojections 77 on a side surface of the front insulator 61, latchingrecessed parts 78, 78 are provided in which not-shown projections, whichare provided on the inner surface of the housing 6, are latched, therebymaking it possible to rotationally lock the stator 9 and to position thestator 9 in the front-rear direction. However, instead of forming boththe projections 77 and the latching recessed parts 78, either one alonemay be formed. In addition, the present teachings are not limited toembodiments in which both the rotational locking of the stator 9 and theforward-rearward positioning of the stator 9 are effected, and thepresent teachings encompass embodiments in which either the rotationallocking or the forward-rearward positioning alone is effected.

Six slots 79 are respectively formed between circumferentially adjacentpairs of teeth 63. On the outer sides of three of the slots 79, whichare adjacent in a semicircular portion (area in plan view) of the frontinsulator 61, three upward-protruding retaining parts 82 are provided torespectively hold three fusing terminals (electrical connectionterminals) 81. Each fusing terminal 81 electrically connects (fuses) awire 101 of each pair of the coils 64 for one phase with a respectivepower-supply line 80 for the corresponding phase. In the retaining parts82, a pair of projections 83, which forms a U shape in a plan view, issequentially arranged in a circumferential direction of the frontinsulator 61 and such that the projections 83 are oriented opposing oneanother. The projections 83 are provided such that they extend to aheight that protrudes farther upward than a ring-shaped (annular)upper-end surface 61 a of the front insulator 61. Between three of theretaining parts 82, L-shaped (in side view) hooks 84 for holding thepower-supply lines 80 are provided such that they protrude from theouter sides of the teeth 63.

In addition, on the outer side of the tooth 63 that is located betweenthe retaining parts 82 and on the outer sides of the two teeth 63 thatare located two teeth away from said tooth 63 in the circumferentialdirections (i.e., at vertex positions of a regular triangle), threescrew bosses 85 for screw fastening the sensor-circuit board 65 areprovided such that they are lower than the retaining parts 82 and extendto a height that protrudes farther upward than the upper-end surface 61a of the front insulator 61. Stepped bosses 86A, 86B, which havereceiving surfaces 87 of a height the same as that of the screw bosses85 and wherein are provided bosses 88A, 88B that protrude farther upwardthan the receiving surfaces 87, are provided such that they protrudefrom the outer sides of the teeth 63 located between the screw bosses85. The boss 88A of the stepped boss 86A is disposed along a concentriccircle that is slightly smaller than the concentric circle of the screwbosses 85, and the diameter of the boss 88B is smaller than that of theboss 88A.

On the rear insulator 62, insulating ribs 89 are disposed along thecircumferential direction and are uprightly (perpendicularly) providedon the outer sides of the slots 79.

In the sensor-circuit board 65, six notched parts (notches) 91, whichare curved toward a through hole 90 for the rotary shaft 11 provided atthe center of the sensor-circuit board 65, are formed equispaced in thecircumferential direction. Six fixing pieces 92, which serve as fixingparts that protrude in radial directions, are formed equispaced in thecircumferential direction. Each fixing piece 92 is formed between acircumferentially-adjacent pair of notched parts 91. Furthermore, eachnotched part 91 extends beyond an inner circumference of the stator core60 and curves to a location that overlaps its corresponding slot 79 inplan view. In addition, a tip of each fixing piece 92 extends slightlybeyond an outer circumference of the stator core 60. Two adjacent fixingpieces 92 (hereinbelow indicated as 92A, 92B when they aredistinguished) are formed longer than the other four fixing pieces 92.

Threaded holes 93 corresponding to the screw bosses 85 are formed in thethree fixing pieces 92 that are located at the vertices of a regulartriangle that includes the one long fixing piece 92B (see e.g., FIG. 6).A first positioning hole 94A, which corresponds to the boss 88A of thestepped boss 86A, and a second positioning hole 94B, which correspondsto the boss 88B of the stepped boss 86B, are formed in two of the otherfixing pieces 92, which are located between the three fixing pieces 92in which the threaded holes 93 are formed. A connection part 95 for sixlead wires 96, which respectively output detection signals generated bythe three rotation-detection devices 66, is provided on an upper surfaceof the remaining one fixing piece 92A. The three rotation-detectiondevices 66 are disposed at a prescribed spacing around the through hole90 on a lower surface of the sensor-circuit board 65.

Each fusing terminal 81 is made by folding a strip-shaped metal plate intwo, thereby forming L-shaped wing pieces 98, 98 on both sides of oneplate part 97A. Then, a tip of another plate part 97B is folded towardthe outer side. With the double-folded portion set downward, the wingpieces 98 are respectively inserted, from above, into the twoprojections 83 of the corresponding retaining part 82, and thereby thefusing terminal 81 is held with an attitude such that the plate part 97Bis located on the outer side and a V shape is open upward. As shown inFIG. 13, a curled part 99, in which the power-supply lines 80 fit, isformed on an inner side of the double-folded portion; on an upper sidethereof, a bent part 100 is formed in which the wire 101 of the coils 64is pinched by the plate part 97B. A folded-back portion 100 a is formedat an upper, outer side end of the plate portion 97B.

Thus, the fusing terminals 81 are disposed such that they are gathered,by the retaining parts 82, on one semicircular side (in one semicirculararea) of the stator 9 in plan view.

In the present embodiment, the six coils 64 are formed by sequentiallywinding one (i.e. a single continuous) wire 101 around every tooth 63,and then two coils 64 of each phase are connected to a respective fusingterminal 81. Furthermore, crossover wires 102 (i.e. crossover wires102U, 102V, 102W), each of which interconnects the coils 64 of one phasethat are located diagonally opposite one another, are wired (disposed)on the rear insulator 62 side and not on the front insulator 61 side.Various coil-winding methods are explained below, wherein, if there is aneed to distinguish the three phases of U, V, and W, then the letters U,V, and W are appended to the reference numbers of the constituent parts,and the numerals 63U1, 63U2, 64U1, 64U2 and the like are furtherappended if the teeth 63, the coils 64, and the like, which form pairsfor each phase, are distinguished.

FIG. 15 includes two schematic drawings that show a winding method,wherein FIG. 15A is the wiring-connection side (the front insulator 61side) and FIG. 15B is the opposite wiring-connection side (the rearinsulator 62 side). Reference numbers 81U, 81V, 81W are the fusingterminals. The circled-plus symbols indicate wires wound on the far sideorthogonal to the paper surface, and the circled black-dot symbolsindicate wires wound on the near side orthogonal to the paper surface.In addition, the following explanation of the wiring-connection side andthe opposite wiring-connection side assumes that the counterclockwisedirection is left and the clockwise direction is right.

First, a start end 101 a is temporarily fixed, on the wiring-connectionside, to the fusing terminal 81U, whereto a U-phase power-supply line80U has been temporarily fixed.

Then, the coil 64U1 is formed by winding from the right side around thetooth 63U1, which is located on the left side of the fusing terminal81U, and then led out, on the opposite wiring-connection side, on theleft side of the tooth 63U1; a crossover wire 102U, shown by asolid-lined arrow, is pulled clockwise around on the outer sides of theinsulating ribs 89 as a substantially semicircular portion, after whichthe coil 64U2 is formed by winding from the right side around thediagonally-opposite tooth 63U2. Furthermore, the wire 101 is led out, onthe wiring-connection side, from the left side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto a W-phasepower-supply line 80W has been temporarily fixed.

Next, a coil 64W1 is formed by winding from the right side around atooth 63W1, which is adjacent to the left side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63W1; a crossover wire 102W, which is shown by adotted line, is pulled clockwise around on the outer sides of theinsulating ribs 89 as a substantially semicircular portion, after whicha coil 64W2 is formed by winding from the right side around thediagonally-opposite tooth 63W2. Subsequently, it is led out, on the sameopposite wiring-connection side, on the left side of the tooth 63W2; thecrossover wire 102W is pulled clockwise around on the outer sides of theinsulating ribs 89 as a substantially semicircular portion andsubsequently led out, on the wiring-connection side, on the left side ofthe diagonally-opposite tooth 63W1 and is temporarily fixed to thefusing terminal 81V, whereto a V-phase power-supply line 80V has beentemporarily fixed. That is, the wire 101 that forms the W-phase coils64W 1, 64W2 is wired, a substantially semicircular portion at a time, onthe rear insulator 62 side clockwise between the diagonally-oppositeteeth 63W1, 63W2.

Next, a coil 64V1 is formed by winding from the right side around atooth 63V1, which is adjacent to the left side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63V1; a crossover wire 102V, shown by a chainline, is pulled clockwise around on the outer sides of the insulatingribs 89 as a substantially semicircular portion, after which the coil64V2 is formed by winding from the right side around thediagonally-opposite tooth 63V2. Subsequently, it is led out, on the sameopposite wiring-connection side, on the left side of the tooth 63V2; thecrossover wire 102V is pulled clockwise around on the outer sides of theinsulating ribs 89 as a substantially semicircular portion and issubsequently led out, on the wiring-connection side, on the left side ofthe diagonally-opposite tooth 63V1; a terminal end 101 b is temporarilyfixed to the fusing terminal 81U, which is adjacent to the left side ofthe tooth 63V1. That is, the wire 101 that forms the V-phase coils 64V1,64V2 also is wired, a substantially semicircular portion at a time, onthe rear insulator 62 side counterclockwise between thediagonally-opposite teeth 63V1, 63V2.

Lastly, when the power-supply lines 80 and the wire 101 are electricallyconnected (fused) at each of the respective fusing terminals 81, thestator 9 is obtained wherein the coils 64 of each phase are deltaconnected.

After the wiring connection has been completed in this manner, in thesensor-circuit board 65, the three fixing pieces 92, in which thethreaded holes 93 are formed, are aligned with the three screw bosses85. Then, the first positioning hole 94A is inserted into the boss 88Aof the stepped boss 86A and the second positioning hole 94B is insertedinto the boss 88B of the stepped boss 86B. Thereafter, the fixing pieces92 are fixed to the screw bosses 85 by screws 103, whereupon thesensor-circuit board 65 is supported, orthogonal to the axis line of thestator 9 and at a location upward of the upper-end surface 61 a of thefront insulator 61, by the upper surfaces of the screw bosses 85 and thereceiving surfaces 87 of the stepped bosses 86A, 86B. At this time, thetips of the hooks 84, too, make contact with the lower surfaces of thelong fixing pieces 92A, 92B, thereby supporting these fixing pieces 92A,92B. In this embodiment, the crossover wires 102 between the coils 64 ofeach phase are wired on the opposite wiring-connection side, andtherefore a sufficient gap is formed (provided) between the frontinsulator 61 and the sensor-circuit board 65. In addition, in the statewherein the sensor-circuit board 65 is fixed, the retaining parts 82 andfusing terminals 81 pass through the notched parts (notches) 91 of thesensor-circuit board 65 and protrude upward from the sensor-circuitboard 65. Furthermore, the slots 79 between each of the teeth 63 in planview are exposed to (fluidly communicate with) the interiors of thenotched parts (notches) 91 of the sensor-circuit board 65 (see e.g.,FIG. 7).

Because the power-supply lines 80 are held by the hooks 84 and thefixing pieces 92, the power-supply lines 80 tend not to move and alsobecome guides during the wiring. In addition, because the fixing piece92A, to which the lead wires 96 of the rotation-detection devices 66 areconnected, is supported by one of the hooks 84, the lead wires 96 tendnot to disconnect. Furthermore, because the distance in a radialdirection from the axial center of the brushless motor 8 to the centerof the boss 88A is less (smaller) than the distance in the radialdirection from that axial center to the centers of the screws 103,vibration of the sensor-circuit board 65 during operation is inhibited.

In the stator 9, the fusing terminals 81 are incorporated into thehousing 6 at phases (intervals) located on a lower-half side (within asemicircular (180°) arc) of the stator 9. Consequently, the power-supplyline 80 of each phase connected to its corresponding fusing terminal 81is wired via the shortest distance to the controller 20 side withoutpassing through the left and right outer sides of the stator 9. As aresult, this wiring scheme does not require an increase of the size ofthe housing 6 in the radial direction, thereby making it possible toreduce the size of the housing 6 (make it more compact) and to make dowith a short length of wiring.

In the hammer driver-drill 1 configured as described above, when theswitch 14 is turned ON by squeezing the trigger 15, the microcontrollerof the controller 20 acquires the rotational state of the rotor 10 byreceiving rotation-detection signals, which are output from therotation-detection devices 66 of the sensor-circuit board 65, thatindicate the positions of the permanent magnets 68 of the rotor 10,controls the ON/OFF state of the switching devices in accordance withthe acquired rotational state, and rotates the rotor 10 by sequentiallysupplying electric current to the coils 64 of each phase of the stator9. Consequently, the rotary shaft 11 rotates, which rotates the spindle13 via the planetary-gear speed-reducing mechanism 33; thus, usage inthe operation mode selected for the particular tool accessory (tip tool)chucked (held) by the drill chuck 4 becomes possible.

When the centrifugal fan 70 rotates together with the rotation of therotary shaft 11, outside air is sucked in via the air-suction ports 72on the side surfaces of the housing 6, passes over the outer side of thestator 9 and the inner side (within the interior) of the stator 9(between the stator 9 and the rotor 10), and is discharged via theair-exhaust ports 71, thereby cooling the brushless motor 8. As wasdescribed above, in the stator 9, the slots 79 are exposed, in a sideview, by the notched parts (notches) 91 of the sensor-circuit board 65.Furthermore, because the crossover wires 102 are not wired between thesensor-circuit board 65 and the front insulator 61, the air that passesthrough the inner side of the stator 9 can pass smoothly through theslots 79 on both sides of the coils 64 without being hindered by thesensor-circuit board 65. Consequently, each of the coils 64 iseffectively cooled. In addition, because the fusing terminals 81 arelocated between the fixing pieces 92, 92, the fusing terminals 81 arealso effectively cooled by the air that passes through the notched parts(notches) 91.

Moreover, in the rotor 10, the front stopper 74 and the rear stopper 73are provided at the front and rear, respectively, and consequentlymovement of the permanent magnets 68 in the front-rear direction isrestricted or prevented and the permanent magnets 68 are effectivelyprevented from coming off of the rotor core 67.

Thus, according to the hammer driver-drill 1 of the above-describedembodiment, the notched parts 91, which are located between adjacentteeth 63 in the axial direction of the stator 9, are formed on the outercircumference of the sensor-circuit board 65.

Therefore the air for cooling the brushless motor 8 easily passesthrough the inner side (interior) of the stator 9. As a result, thecoils 64 of the stator 9 can be effectively cooled.

More particularly, because the notched parts 91 are respectively formedbetween the fixing pieces 92, 92, the notched parts 91 can be providedwithout interfering with the attachment of the sensor-circuit board 65.

In addition, by disposing the connection part 95 that holds the leadwires 96 on the sensor-circuit board 65 between two of the notched parts91, even though the notched parts 91 are formed (present), they do notinterfere with the connection of the lead wires 96. Furthermore, becausethe fusing terminals 81 connected to the coils 64 are respectivelydisposed in the notched parts 91, the fusing terminals 81 can also beeffectively cooled.

In addition, there are six of the coils 64, the notched parts 91 areformed at six locations, and the notched parts 91 respectively exposethe coils 64 in the axial direction of the stator 9, which makes itpossible to reliably cool each of the coils 64 of the three phases.

Furthermore, according to the hammer driver-drill 1 of theabove-described embodiment, the fusing terminals 81, which are connectedto the coils 64 and connected to the power-supply lines 80, are providedon the front insulator 61, which is a first electrically insulatingmember whereon the sensor-circuit board 65 is fixed on theouter-circumference side. Therefore the sensor-circuit board 65 can beeasily detached from the stator 9.

More particularly, because the sensor-circuit board 65 is screw-fastenedonto the front insulator 61, the mounting and dismounting of thesensor-circuit board 65 can be performed simply.

In addition, because three of the fusing terminals 81 are provided andthe coils 64 are delta connected, the wiring of the coils 64 of thethree phases can be performed easily.

Furthermore, because the fusing terminals 81 are disposed betweenadjacent teeth 63, the wiring connection of the wire 101 of the coils 64wound on the teeth 63 can be performed easily.

In addition, because the connection part 95 that holds the lead wires 96is disposed between two of the fusing terminals 81, the lead wires 96can be routed without interfering with the fusing terminals 81.

Moreover, according to the hammer driver-drill 1 of the above-describedembodiment, the grooves 75 are provided, along the axial direction ofthe stator 9, at (on) the outer circumference of the stator core 60, andthe mating pieces 76, which mate with the grooves 75, are formedintegrally with the front and rear insulators 61, 62. Therefore thestator core 60 and the front and rear insulators 61, 62 can be rigidlyintegrated (connected) and in a manner that resists or inhibits warpageof the front and rear insulators 61, 62 over time.

Furthermore, according to the hammer driver-drill 1 of theabove-described embodiment, the three fusing terminals 81 are disposedwithin a semicircular-portion area of the stator core 60, and thereforethe wiring space for the power-supply lines 80 is reduced.

Moreover, the routing of the power-supply lines 80 also becomes easy andis shortened. Consequently, the housing 6 can be made more compact.

In addition, because a portion of the crossover wires 102 of the wire101 forming the coils 64 of each phase is provided on the oppositewiring-connection side (the rear insulator 62 side), the space on thewiring-connection side (the front insulator 61 side) expands. Thisincreases the number of degrees of freedom for the wire routing and thelike, and moreover there is no longer a need to provide the fusingterminals 81 with electrically-insulating parts on the wiring-connectionside.

It is explicitly noted that the numbers of the notched parts and thefixing pieces are not limited to the above-described embodiment and canbe increased or decreased as appropriate. Moreover, the number of screwbosses, stepped bosses, and the like also can be modified as appropriatein accordance with the number of the screw fittings. The stepped bossesmay be omitted. The notched parts are not limited to the bent (curved)shape shown in the drawings and instead may be notched into the shape ofa quadrangle, a trapezoid, a triangle, a semicircle, or the like.

In addition, it is not necessary to provide the notched parts incorrespondence with all of the slots, and it is possible to providefewer of the notched parts than there are slots, as long as the coolingeffect of the coils produced by the passage of the air is obtained.

Accordingly, it is also conceivable to provide the notched parts suchthat they expose a plurality of slots and to dispose two or more offusing terminals within one notched part.

Furthermore, in the above-described embodiment, the sensor-circuit boardis provided on the front insulator, but it is also possible to providethe sensor-circuit board on the rear insulator and to wire (dispose) thecrossover wires on the front insulator side.

Furthermore, wire-winding methods according to the present teachings arenot limited to the method described in connection with FIG. 15 and canbe modified as appropriate. A variety of modified examples will beexplained below, with reference to the schematic drawings. Furthermore,in the schematic drawings, too, the “A” portion of the

Figure shows the wiring-connection side (the front insulator 61 side)and the “B” portion of the Figure shows the opposite wiring-connectionside (the rear insulator 62 side), and constituent parts the same asthose in FIG. 15 are assigned the same reference numbers, and redundantexplanations are omitted. In the modified example shown in FIG. 16,first, the start end 101 a is temporarily fixed on the wiring-connectionside to the fusing terminal 81U, whereto the U-phase power-supply line80U has been temporarily fixed. Then, the coil 64U1 is formed by windingfrom the right side around the tooth 63U1, which is located on the leftside of the fusing terminal 81U, and is then led out, on the oppositewiring-connection side, on the left side of the tooth 63U1; thecrossover wire 102U is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion, afterwhich the coil 64U2 is formed by winding from the right side around thediagonally-opposite tooth 63U2. Furthermore, the wire 101 is led out, onthe wiring-connection side, from the left side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the right side around thetooth 63W1, which is adjacent to the left side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63W1; the crossover wire 102W

MAK069-00656 (PA-15039-US) is pulled counterclockwise around on theouter sides of the insulating ribs 89 as a substantially semicircularportion, after which the coil 64W2 is formed by winding from the rightside around the diagonally-opposite tooth 63W2. Subsequently, it is ledout, on the same opposite wiring-connection side, on the left side ofthe tooth 63W2; the crossover wire 102W is pulled counterclockwisearound on the outer sides of the insulating ribs 89 as a substantiallysemicircular portion, after which it is led out, on thewiring-connection side, on the left side of the diagonally-oppositetooth 63W1 and is temporarily fixed to the fusing terminal 81V, wheretothe V-phase power-supply line 80V has been temporarily fixed. That is,the wire 101 that forms the W-phase coils 64W 1, 64W2 is wired, asubstantially semicircular portion at a time, on the rear insulator 62side counterclockwise between the teeth 63W1, 63W2, and the crossoverwires 102W, 102W cross one another at the teeth 63W1, 63W2.

Next, the coil 64V1 is formed by winding from the right side around thetooth 63V1, which is adjacent to the left side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63V1; the crossover wire 102V is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64V2 isformed by winding from the right side around the diagonally-oppositetooth 63V2. Subsequently, it is led out, on the same oppositewiring-connection side, on the left side of the tooth 63V2; thecrossover wire 102V is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion, thenled out, on the wiring-connection side, on the left side of thediagonally-opposite tooth 63V1, and the terminal end 101 b istemporarily fixed to the fusing terminal 81U, which is adjacent to theleft side of the tooth 63V1. That is, the wire 101 that forms theV-phase coils 64V1, 64V2 also is wired, a substantially semicircularportion at a time, on the rear insulator 62 side counterclockwisebetween the teeth 63V1, 63V2. Because the crossover wires 102V, 102Vcross one another at the teeth 63V1, 63V2, a maximum of four of thecrossover wires 102 overlap.

In the modified example shown in FIG. 17, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the right sidearound the tooth 63U1, which is located on the left side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the left side of the tooth 63U1; the crossover wire 102U ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64U2 isformed by winding from the right side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the left side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the right side around thetooth 63W1, which is adjacent to the left side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63W1; the crossover wire 102W is pulled clockwisearound on the outer sides of the insulating ribs 89 as a substantiallysemicircular portion, after which the coil 64W2 is formed by windingfrom the right side around the diagonally-opposite tooth 63W2.Subsequently, it is led out, on the same opposite wiring-connectionside, on the left side of the tooth 63W2; the crossover wire 102W ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, then is led out, on thewiring-connection side, on the left side of the diagonally-oppositetooth 63W1 and is temporarily fixed to the fusing terminal 81V, wheretothe V-phase power-supply line 80V has been temporarily fixed. That is,the wire 101 that forms the W-phase coils 64W 1, 64W2 is wired, asubstantially semicircular portion at a time, on the rear insulator 62side clockwise between the teeth 63W1, 63W2.

Next, the coil 64V1 is formed by winding from the right side around thetooth 63V1, which is adjacent to the left side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63V1; the crossover wire 102V is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64V2 isformed by winding from the right side around the diagonally-oppositetooth 63V2. Subsequently, it is led out, on the wiring-connection side,on the left side of the tooth 63V2; the crossover wire 102V is pulledcounterclockwise around as a substantially semicircular portion, afterwhich the terminal end 101 b is temporarily fixed to the fusing terminal81U. That is, the wire 101 that forms the V-phase coils 64V1, 64V2 isdivided into the rear insulator 62 side and the front insulator 61 sideand is wound, a substantially semicircular portion at a time,counterclockwise between the teeth 63V1, 63V2. Therefore, even thoughone of the crossover wires 102 exists on the wiring-connection side,there is a maximum overlap of three crossover wires 102 on the oppositewiring-connection side, which is one fewer than the embodiment shown inFIG. 16.

In the modified example shown in FIG. 18, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the right sidearound the tooth 63U1, which is located on the left side of the fusingterminal 81U, and is then led out, on the opposite wiring-connectionside, on the left side of the tooth 63U1; the crossover wire 102U ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64U2 isformed by winding from the right side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the left side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the right side onto thetooth 63W1, which is adjacent to the left side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63W1; the crossover wire 102W is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64W2 isformed by winding from the right side around the diagonally-oppositetooth 63W2. Subsequently, it is led out, on the same oppositewiring-connection side, on the left side of the tooth 63W2; thecrossover wire 102W is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion andthen is led out, on the wiring-connection side, on the left side of thediagonally-opposite tooth 63W1 and is temporarily fixed to the fusingterminal 81V, whereto the V-phase power-supply line 80V has beentemporarily fixed. That is, the wire 101 that forms the W-phase coils64W 1, 64W2 is wired counterclockwise on the rear insulator 62 sidebetween the teeth 63W1, 63W2 by a substantially semicircular portion ata time, and the crossover wires 102W, 102W cross one another at theteeth 63W 1, 63W2.

Next, the coil 64V1 is formed by winding from the right side around thetooth 63V1, which is adjacent to the left side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theleft side of the tooth 63V1; the crossover wire 102V is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64V2 isformed by winding from the right side around the diagonally-oppositetooth 63V2. Subsequently, it is led out, on the wiring-connection side,on the left side of the tooth 63V2; the crossover wire 102V is pulledcounterclockwise around as a substantially semicircular portion, afterwhich the terminal end 101 b is temporarily fixed to the fusing terminal81U. That is, the wire 101 that forms the V-phase coils 64V1, 64V2 isdivided into the rear insulator 62 side and the front insulator 61 sideand wired counterclockwise between the teeth 63V1, 63V2 as asubstantially semicircular portion at a time. Thereby, even though oneof the crossover wires 102 exists on the wiring-connection side, amaximum of three of the crossover wires 102 overlap on the oppositewiring-connection side, which is one fewer than the embodiment shown inFIG. 16.

In a modified example described below, the arrangement of the phases ofthe fusing terminals 81 and the winding directions of the coils 64 arethe reverse of the example shown in FIG. 15 to FIG. 18. In the modifiedexample shown in FIG. 19, first, the start end 101 a is temporarilyfixed, on the wiring-connection side, to the right-most fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the left sidearound the tooth 63U1, which is located on the right side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the right side of the tooth 63U1; the crossover wire 102U ispulled counterclockwise around on the outer sides of the insulating ribs89 as a substantially semicircular portion, after which the coil 64U2 isformed by winding from the left side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the left side around thetooth 63W1, which is adjacent to the right side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63W1; the crossover wire 102W is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64W2 isformed by winding from the left side around the diagonally-oppositetooth 63W2. Subsequently, it is led out, on the same oppositewiring-connection side, on the right side of the tooth 63W2; thecrossover wire 102W is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion andsubsequently is led out, on the wiring-connection side, on the rightside of the diagonally-opposite tooth 63W1 and is temporarily fixed tothe fusing terminal 81V, whereto the V-phase power-supply line 80V hasbeen temporarily fixed. That is, the wire 101 that forms the W-phasecoils 64W 1, 64W2 is wired, a substantially semicircular portion at atime, on the rear insulator 62 side counterclockwise between the teeth63W1, 63W2.

Next, the coil 64V1 is formed by winding from the left side around thetooth 63V1, which is adjacent to the right side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63V1; the crossover wire 102V is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64V2 isformed by winding from the left side around the diagonally-oppositetooth 63V2. Subsequently, it is led out, on the same oppositewiring-connection side, on the right side of the tooth 63V2; thecrossover wire 102V is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion andsubsequently is led out, on the wiring-connection side, on the rightside of the tooth 63V1. Then, the terminal end 101 b is temporarilyfixed to the fusing terminal 81U. That is, the wire 101 that forms theV-phase coils 64V1, 64V2 also is wired on the rear insulator 62 sidecounterclockwise a substantially semicircular portion at a time betweenthe teeth 63V1, 63V2.

In the modified example shown in FIG. 20, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the left sidearound the tooth 63U1, which is located on the right side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the right side of the tooth 63U1; the crossover wire 102U ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64U2 isformed by winding from the left side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the left side around thetooth 63W1, which is adjacent to the right side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63W1; the crossover wire 102W is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64W2 is formedby winding from the left side around the diagonally-opposite tooth 63W2.Subsequently, it is led out, on the same opposite wiring-connectionside, on the right side of the tooth 63W2; the crossover wire 102W ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which it is led out, on thewiring-connection side, on the right side of the diagonally-oppositetooth 63W1 and is temporarily fixed to the fusing terminal 81V, wheretothe V-phase power-supply line 80V has been temporarily fixed. That is,the wire 101 that forms the W-phase coils 64W 1, 64W2 is wired, on therear insulator 62 side, clockwise a substantially semicircular portionat a time between the teeth 63W1, 63W2, and the crossover wires 102W,102W cross one another at the teeth 63W 1, 63W2.

Next, the coil 64V1 is formed by winding from the left side around thetooth 63V1, which is adjacent to the right side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63V1; the crossover wire 102V is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64V2 is formedby winding from the left side around the diagonally-opposite tooth 63V2.Subsequently, it is led out, on the same opposite wiring-connectionside, on the right side of the tooth 63V2; the crossover wire 102V ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, then is led out, on thewiring-connection side, on the right side of the diagonally-oppositetooth 63V1, and the terminal end 101 b is temporarily fixed to thefusing terminal 81U, which is adjacent to the right side of the tooth63V1. That is, the wire 101 that forms the V-phase coils 64V1, 64V2 alsois wired, on the rear insulator 62 side, clockwise a substantiallysemicircular portion at a time between the teeth 63V1, 63V2.Furthermore, because the crossover wires 102V, 102V cross one another atthe teeth 63V1, 63V2, a maximum of four of the crossover wires 102overlap.

In the modified example shown in FIG. 21, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the left sidearound the tooth 63U1, which is located on the right side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the right side of the tooth 63U1; the crossover wire 102U ispulled counterclockwise around on the outer sides of the insulating ribs89 as a substantially semicircular portion, after which the coil 64U2 isformed by winding from the left side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the left side around thetooth 63W1, which is adjacent to the right side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63W1; the crossover wire 102W is pulledcounterclockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, after which the coil 64W2 isformed by winding from the left side around the diagonally-oppositetooth 63W2. Subsequently, it is led out, on the same oppositewiring-connection side, on the right side of the tooth 63W2; and thecrossover wire 102W is pulled counterclockwise around on the outer sidesof the insulating ribs 89 as a substantially semicircular portion andthen led out, on the wiring-connection side, on the right side of thediagonally-opposite tooth 63W1 and is temporarily fixed to the fusingterminal 81V, whereto the V-phase power-supply line 80V has beentemporarily fixed. That is, the wire 101 that forms the W-phase coils64W 1, 64W2 is wired, on the rear insulator 62 side, counterclockwise asubstantially semicircular portion at a time between the teeth 63W1,63W2.

Next, the coil 64V1 is formed by winding from the left side around thetooth 63V1, which is adjacent to the right side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63V1; the crossover wire 102V is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64V2 is formedby winding from the left side around the diagonally-opposite tooth 63V2.Subsequently, it is led out, on the wiring-connection side, on the rightside of the tooth 63V2; the crossover wire 102V is pulled clockwisearound as a substantially semicircular portion, after which the terminalend 101 b is temporarily fixed to the fusing terminal 81U. That is, thewire 101 that forms the V-phase coils 64V1, 64V2 is divided into therear insulator 62 side and the front insulator 61 side and woundclockwise a substantially semicircular portion at a time between theteeth 63V1, 63V2. Thus, even though one of the crossover wires 102exists on the wiring-connection side, there is a maximum overlap ofthree of the crossover wires 102 on the opposite wiring-connection side,which is one fewer than the embodiment shown in FIG. 20.

In the modified example shown in FIG. 22, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the left sidearound the tooth 63U1, which is located on the right side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the right side of the tooth 63U1; the crossover wire 102U ispulled counterclockwise around on the outer sides of the insulating ribs89 as a substantially semicircular portion, after which the coil 64U2 isformed by winding from the left side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed to the fusing terminal 81W, whereto the W-phasepower-supply line 80W has been temporarily fixed.

Next, the coil 64W1 is formed by winding from the left side around thetooth 63W1, which is adjacent to the right side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63W1; the crossover wire 102W is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64W2 is formedby winding from the left side around the tooth 63W2 on the diagonal.Subsequently, it is led out, on the same opposite wiring-connectionside, on the right side of the tooth 63W2; the crossover wire 102W ispulled clockwise around on the outer sides of the insulating ribs 89 asa substantially semicircular portion, and then is led out, on thewiring-connection side, on the right side of the diagonally-oppositetooth 63W1 and is temporarily fixed to the fusing terminal 81V, wheretothe V-phase power-supply line 80V has been temporarily fixed. That is,the wire 101 that forms the W-phase coils 64W 1, 64W2 is wired, on therear insulator 62 side, clockwise by a substantially semicircularportion at a time between the teeth 63W1, 63W2, and the crossover wires102W, 102W cross one another at the teeth 63W1, 63W2.

Next, the coil 64V1 is formed by winding from the left side around thetooth 63V1, which is adjacent to the right side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63V1; the crossover wire 102V is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64V2 is formedby winding from the left side around the diagonally-opposite tooth 63V2.Subsequently, it is led out, on the wiring-connection side, on the rightside of the tooth 63V2; the crossover wire 102V is pulled clockwisearound as a substantially semicircular portion, after which the terminalend 101 b is temporarily fixed to the fusing terminal 81U. That is, thewire 101 that forms the V-phase coils 64V1, 64V2 is divided into therear insulator 62 side and the front insulator 61 side and wiredclockwise a substantially semicircular portion at a time between theteeth 63V1, 63V2. Thus, even though one of the crossover wires 102exists on the wiring-connection side, a maximum of three of thecrossover wires 102 overlap on the opposite wiring-connection side,which is one fewer than the embodiment shown in FIG. 20.

In the modified example shown in FIG. 23, first, the start end 101 a istemporarily fixed, on the wiring-connection side, to the fusing terminal81U, whereto the U-phase power-supply line 80U has been temporarilyfixed. Then, the coil 64U1 is formed by winding from the left sidearound the tooth 63U1, which is located on the right side of the fusingterminal 81U, and then is led out, on the opposite wiring-connectionside, on the right side of the tooth 63U1; the crossover wire 102U ispulled counterclockwise around on the outer sides of the insulating ribs89 as a substantially semicircular portion, after which the coil 64U2 isformed by winding from the left side around the diagonally-oppositetooth 63U2. Furthermore, the wire 101 is led out, on thewiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed, in a folded-back state, to the fusing terminal 81W,whereto the W-phase power-supply line 80W has been temporarily fixed.

Next, the crossover wire 102W is pulled clockwise from the fusingterminal 81W as a substantially semicircular portion, and the coil 64W2is formed by winding from the left side around the tooth 63W2, which isadjacent to the right side of the tooth 63U1. Then, it is led out, onthe opposite wiring-connection side, on the right side of the tooth63W2; the crossover wire 102W is pulled clockwise around on the outersides of the insulating ribs 89 as a substantially semicircular portion,after which the coil 64W1 is formed by winding from the left side aroundthe diagonally-opposite tooth 63W1. Subsequently, it is led out, on thewiring-connection side, on the right side of the tooth 63W1 and istemporarily fixed to the fusing terminal 81V, whereto the V-phasepower-supply line 80V has been temporarily fixed. That is, the wire 101that forms the W-phase coils 64W 1, 64W2 is divided into the frontinsulator 61 side and the rear insulator 62 side and is wired clockwisea substantially semicircular portion at a time.

Next, the coil 64V1 is formed by winding from the left side around thetooth 63V1, which is adjacent to the right side of the fusing terminal81V. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63V1; the crossover wire 102V is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64V2 is formedby winding from the left side around the diagonally-opposite tooth 63V2.Subsequently, it is led out, on the wiring-connection side, on the rightside of the tooth 63V2; the crossover wire 102V is pulled clockwisearound as a substantially semicircular portion, after which the terminalend 101 b is temporarily fixed to the fusing terminal 81U. That is, thewire 101 that forms the V-phase coils 64V1, 64V2 also is divided intothe front insulator 61 side and the rear insulator 62 side and is wiredclockwise a substantially semicircular portion at a time.

In the modified example shown in FIG. 24, the locations of the fusingterminals 81V, 81W are the reverse of that shown in FIG. 23. First, thestart end 101 a is temporarily fixed, on the wiring-connection side, tothe fusing terminal 81U, whereto the U-phase power-supply line 80U hasbeen temporarily fixed. Then, the coil 64U1 is formed by winding fromthe left side around the tooth 63U1, which is located on the right sideof the fusing terminal 81U, and then led out, on the oppositewiring-connection side, on the right side of the tooth 63U1; thecrossover wire 102U is pulled clockwise around on the outer sides of theinsulating ribs 89 as a substantially semicircular portion, after whichthe coil 64U2 is formed by winding from the left side around thediagonally-opposite tooth 63U2. Furthermore, the wire 101 is led out, onthe wiring-connection side, from the right side of the tooth 63U2 and istemporarily fixed, in a folded-back state, to the fusing terminal 81V,whereto the V-phase power-supply line 80V has been temporarily fixed.

Next, the crossover wire 102V is pulled clockwise around from the fusingterminal 81V, and the coil 64V2 is formed by winding from the left sidearound the tooth 63V2, which is adjacent to the left side of the tooth63U2. Then, it is led out, on the opposite wiring-connection side, onthe right side of the tooth 63V2; the crossover wire 102V is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64V1 is formedby winding from the left side around the diagonally-opposite tooth 63V1.Subsequently, it is pulled clockwise around, on the wiring-connectionside, from the right side of the tooth 63V1 and is temporarily fixed tothe fusing terminal 81W, whereto the W-phase power-supply line 80W hasbeen temporarily fixed. That is, the wire 101 that forms the V-phasecoils 64V1, 64V2 is wired on the front insulator 61 side clockwisebetween the fusing terminal 81V and the tooth 63V2 and between the tooth63V1 and the fusing terminal 81W, and is wired on the rear insulator 62side clockwise by a substantially semicircular portion between the teeth63V2, 63V1.

Next, the coil 64W1 is formed by winding from the left side onto thetooth 63W1, which is adjacent to the left side of the fusing terminal81W. Then, it is led out, on the opposite wiring-connection side, on theright side of the tooth 63W1; the crossover wire 102W is pulledclockwise around on the outer sides of the insulating ribs 89 as asubstantially semicircular portion, after which the coil 64W2 is formedby winding from the left side around the diagonally-opposite tooth 63W2.Subsequently, it is led out, on the wiring-connection side, on the rightside of the tooth 63W2, and the crossover wire 102V is pulled clockwisearound, after which the terminal end 101 b is temporarily fixed to thefusing terminal 81U. That is, the wire 101 that forms the W-phase coils64W1, 64W2 also is wired on the front insulator 61 side clockwisebetween the fusing terminal 81W and the tooth 63W1 and between the tooth63W2 and the fusing terminal 81U, and is wired on the rear insulator 62side clockwise by a substantially semicircular portion between the teeth63W1, 63W2.

It is noted that, in the aspects of the present teachings related to thecooling of the coils, the power tool is not limited to a hammerdriver-drill, and the present teachings also can be readily adapted toother types of power tools, such as impact drivers, grinders, etc., aslong as it includes a motor that serves as a drive source and has asensor-circuit board fastened to an electrically insulating member.Accordingly, the position, orientation, etc. of the motor inside thehousing can also be modified as appropriate. In addition, in theabove-described embodiments, the coils are formed by (from) one (asingle continuous) wire (winding wire), but it is also possible to formthe coils using two, three, or a plurality of discrete (discontinuous)winding wires. Of course, the winding routes are not limited to deltaconnections, and e.g., Y connections may also be advantageously usedwith the present teachings.

Moreover, in the aspects of the present teachings related to thearrangement of the terminals, too, the power tool is not limited to ahammer driver-drill, and the present teachings also can be adapted toother types of power tools, such as impact drivers, grinders, etc., aslong as it includes a motor that serves as a drive source and hasterminals, to which coils are wired, provided on an electricallyinsulating member. Accordingly, the area in which the terminals aredisposed may be an upper half, a transverse half, or the like dependingon the type of power tool. Furthermore, even if the three-phase windingis a Y connection, compact designs can still be achieved by thearrangement of the terminals according to the present teachings.

Representative, non-limiting examples of the present invention weredescribed above in detail with reference to the attached drawings. Thisdetailed description is merely intended to teach a person of skill inthe art further details for practicing preferred aspects of the presentteachings and is not intended to limit the scope of the invention.Furthermore, each of the additional features and teachings disclosedabove and below may be utilized separately or in conjunction with otherfeatures and teachings to provide improved power tools.

Moreover, combinations of features and steps disclosed in the abovedetailed description, as well as in the below additional examples, maynot be necessary to practice the invention in the broadest sense, andare instead taught merely to particularly describe representativeexamples of the invention. Furthermore, various features of theabove-described representative examples, as well as the variousindependent and dependent claims below, may be combined in ways that arenot specifically and explicitly enumerated in order to provideadditional useful embodiments of the present teachings.

All features disclosed in the description and/or the claims are intendedto be disclosed separately and independently from each other for thepurpose of original written disclosure, as well as for the purpose ofrestricting the claimed subject matter, independent of the compositionsof the features in the embodiments and/or the claims. In addition, allvalue ranges or indications of groups of entities are intended todisclose every possible intermediate value or intermediate entity forthe purpose of original written disclosure, as well as for the purposeof restricting the claimed subject matter.

EXPLANATION OF THE REFERENCE NUMBERS

1 Hammer driver-drill

2 Main body

3 Handle

4 Drill chuck

5 Battery pack

6 Housing

8 Brushless motor

9 Stator

10 Rotor

11 Rotary shaft

12 Gear assembly

13 Spindle

20 Controller

33 Planetary-gear speed-reducing mechanism

60 Stator core

61 Front insulator

62 Rear insulator

63 Tooth

64 Coil

65 Sensor-circuit board

67 Rotor core

70 Centrifugal fan

71 Air-exhaust port

72 Air-suction port

75 Groove

76 Mating piece

79 Slot

80 Power-supply line

81 Fusing terminal

82 Retaining part

85 Screw boss

89 Insulating rib

91 Notched part (notch)

92 Fixing piece

95 Connection part

96 Lead wire

101 Wire

101 a Start end

101 b Terminal end

102 Crossover wire

1. A power tool having a motor, comprising: a stator comprising: atubular stator core; one or more electrically insulating members fixedto the stator core; and coils, which are wound around a plurality ofteeth that protrude from an inner side of the stator core; a rotorcomprising: a rotor core disposed on an inner side of the stator; arotary shaft fixed to the rotor core; and one or more permanent magnetsfixed to the rotor core; and a sensor-circuit board configured to detectposition(s) of the permanent magnet(s), the sensor-circuit board beingfixed to the stator; wherein, at least one notched part is formed, in anouter circumference of the sensor-circuit board, such that it is locatedbetween two of the teeth in an axial direction of the stator.
 2. Thepower tool according to claim 1, wherein the stator and thesensor-circuit board are fixed together via fixing parts at at least twopositions located along a circumferential direction of the stator; andthe at least one notched part is formed between the fixing parts.
 3. Thepower tool according to claim 1, wherein the at least one notched partcomprises at least two notched parts that are respectively formed at atleast two locations along a circumferential direction of the stator; andthe sensor-circuit board comprises a connection part configured to holdat least one lead wire that outputs a detection signal, the connectionpart being disposed between the at least two notched parts.
 4. The powertool according to claim 1, wherein the stator comprises at least twoterminals respectively connected to at least two of the coils; the atleast notched part comprises at least two notched parts that arerespectively formed at at least two locations along a circumferentialdirection of the stator; and the terminals are respectively disposed inthe at least two notched parts of the sensor-circuit board.
 5. The powertool according to claim 1, wherein six of the coils are provided; the atleast one notched part comprises six notched parts that are respectivelyformed at six locations along a circumferential direction of thesensor-circuit board; and each of the six notched parts respectivelyexposes one of the six coils in the axial direction of the stator. 6.The power tool according to claim 5, wherein the stator is fixed to thesensor-circuit board via at least three fixing parts respectivelylocated at three positions along the circumferential direction of thesensor-circuit board.
 7. The power tool according to claim 6, whereinthe stator comprises three terminals respectively connected to threepairs of the coils; and the three terminals are respectively disposed inthree of the notched parts of the sensor-circuit board that are adjacentto each other in the circumferential direction of the sensor-circuitboard.
 8. The power tool according to claim 7, wherein thesensor-circuit board comprises a connection part configured to hold atleast one lead wire that outputs a detection signal, the connection partbeing disposed between two of the notched parts.
 9. The power toolaccording to claim 8, wherein the three terminals are respectivelyconnected to power-supply lines for the three pairs of the coils; theone or more electrically insulating members comprise first and secondelectrically insulating members; the three terminals are provided on thefirst electrically insulating member, and the sensor-circuit board isscrew fastened onto the first electrically insulating member.
 10. Thepower tool according to claim 9, wherein a groove is provided on anouter circumference of the stator core and extends along an axialdirection of the stator; first and second mating pieces are respectivelyformed, in an integral manner with the first and second electricallyinsulating members; and the first and second mating pieces both matewith the groove.
 11. A power tool having a motor, comprising: a statorcomprising: a tubular stator core; a first electrically insulatingmember and a second electrically insulating member, which arerespectively fixed to front and rear end surfaces of the stator core;and coils, which are wound around a plurality of teeth that protrudefrom an inner side of the stator core; a rotor comprising: a rotor coredisposed on an inner side of the stator; a rotary shaft fixed to therotor core; and one or more permanent magnets fixed to the rotor core;and a sensor-circuit board configured to detect position(s) of thepermanent magnet(s), the sensor-circuit board being fixed to anouter-circumference side of the first electrically insulating member;wherein, terminals are respectively connected to the coils and topower-supply lines for the coils, the terminals being provided on thefirst electrically insulating member.
 12. The power tool according toclaim 11, wherein the sensor-circuit board is screw fastened onto thefirst electrically insulating member.
 13. The power tool according toclaim 11, wherein three of the terminals are provided; and the coils aredelta connected.
 14. The power tool according to claim 11, wherein theterminals are respectively disposed between circumferentially-adjacentpairs of the teeth.
 15. The power tool according to claim 11, whereintwo of the terminals are provided; and the sensor-circuit boardcomprises a connection part configured to hold a lead wire that outputsa detection signal, the connection part being disposed between the twoterminals.
 16. The power tool according to claim 15, wherein theterminals are respectively disposed between circumferentially-adjacentpairs of the teeth.
 17. The power tool according to claim 16, whereinthe sensor-circuit board is screw fastened onto the first electricallyinsulating member.
 18. The power tool according to claim 17, whereinthree of the terminals are provided; and the coils are delta connected.19. A power tool having a motor, comprising: a stator comprising: atubular stator core; electrically insulating members respectively fixedto front and rear end surfaces of the stator core; and coils, which arewound around a plurality of teeth that protrude from an inner side ofthe stator core; a rotor comprising: a rotor core disposed on an innerside of the stator; a rotary shaft fixed to the rotor core; and one ormore permanent magnets fixed to the rotor core; and a sensor-circuitboard configured to detect position(s) of the permanent magnet(s), thesensor-circuit board being fixed to the stator; wherein, a groove isprovided on an outer circumference of the stator core and extends alongan axial direction of the stator; and mating pieces, which mate with thegroove, are respectively formed integrally with the electricallyinsulating members.
 20. The power tool according to claim 19, whereinthe groove comprises a plurality of grooves provided on the outercircumference of the stator core and each groove extends along the axialdirection of the stator; and a plurality of mating pieces are integrallyformed on each of the electrically insulating members, the plurality ofmating pieces respectively engaging in the plurality of grooves.